ACoS, or Advertising Cost of Sales, is your ad spend divided by the sales those ads produced. A high ACoS usually does not mean your ads are broken. It means a portion of spend is going to clicks that do not convert, bids that are higher than they need to be, or campaigns that compete with each other. Fix those in the right order and ACoS falls without hurting sales.
1. Set your break-even ACoS first
You cannot judge a campaign without knowing your break-even point. Break-even ACoS is roughly equal to your product gross margin. If your margin after COGS, Amazon fees and shipping is 30 percent, then any ad sale above 30 percent ACoS is losing money, and anything below it is profitable. Write this number down. Every decision below is measured against it.
2. Stop the bleed with negative keywords
Pull a Search Term report and find terms with real click volume and zero orders. The key word is "real". A term with three clicks and no sale is not proof of failure, it is just a small sample. Wait until a term has enough clicks that you would expect at least one order at your conversion rate, then add the confirmed losers as negative exact. This single step often removes 10 to 25 percent of wasted spend.
3. Right-size bids against your target
For targets that do convert but sit above break-even, lower the bid toward your target, do not pause them. A good rule: new bid equals current bid multiplied by your target ACoS divided by the current ACoS, and never cut more than about half in one move. For targets already under target ACoS with steady orders, nudge bids up 10 to 20 percent to capture more profitable volume.
4. Fix campaigns that compete with each other
Duplicate keywords across multiple ad groups, and the same term running in exact, phrase and broad at once, make you bid against yourself and inflate CPCs. Isolate match types, keep one clear home for each keyword, and use negatives to stop overlap. Clean structure lowers ACoS on its own.
5. Reallocate budget from losers to winners
Move spend out of above-break-even campaigns and into the profitable, budget-limited ones. A campaign running at 15 percent ACoS that hits its daily cap is leaving money on the table. Feed it.
6. Protect Top of Search and rank
Here is the nuance most guides miss. Top of Search usually carries a higher ACoS, but it also drives organic rank and Buy Box momentum. Do not blanket-cut it just because the number looks high. Judge placement spend on its contribution to total business, not last-click ACoS alone.
7. Watch TACoS, not just ACoS
TACoS, total advertising cost of sales, compares ad spend to your total revenue including organic. A falling TACoS over time means your ads are building organic sales, which is the real goal. ACoS can rise slightly during a healthy push for rank while TACoS still trends down.
Common mistakes that raise ACoS
- Cutting bids before removing wasted search terms.
- Negating terms after only a few clicks, which suppresses future winners.
- Running auto, broad and exact for the same term without negatives.
- Defunding Top of Search and losing organic rank.
- Judging brand-new launches by the same ACoS target as mature products.
Do these in order and most accounts see ACoS move within two to four weeks, because you are removing waste and overspend rather than starving demand. If you want a second pair of eyes, our Amazon PPC management team does this end to end.